Background: Mammary carcinoma possesses multiple morphological expressions, classified into subtypes based on histological grade and receptors expression. In spite of various screening and prevention programs implementation its incidence is still on the top among malignant diseases. The aim: assessment of EGFR expression based on tumor’s histological type and grade of differentiation and determining of this factor stability within the metastatic process. Material and methods: there were examined primary tumors and ipsilateral axillary lymph node metastasis, collected from 85 patients with mammary ductal invasive carcinoma of NOS (not otherwise specified) type and 18 patients with lobular invasive carcinoma, using conventional histological and immunohistochemical (IHC) techniques. With the help of IHC has been determined the expression of receptor for Epidermal Growth Factor (EGFR). Results: in ductal invasive carcinoma we obtained weak but statistically significant correlation between histological grade and age of patients (rs=0,23, p<0,03). Comparing the values of EGFR expression in both locations, we obtained in 6 cases (15.8%) the expression’s score transfer. All these transfers have been characterized by the loosing of positive pattern in lymph node microenvironment and were found in both age groups: “before 49 years” and “after 49 years”. In lobular invasive carcinoma also have been obtained statistically significant correlation between EGFR score of expression and patients age (rs=0,45, p<0,031). The age correlated with the grade of differentiation, as well (rs=0,57, p<0,007). Comparing the values of EGFR in both locations, we determined that the scores of EGFR are statistically different (t=2,12, with an p<0,05). However the correlation test highlighted strong positive association between EGFR values in primary tumor and metastasis. Conclusions: ductal invasive mammary carcinoma of NOS type could in an equal manner EGFR positive or negative. Histological grade of these tumors positively correlates with the patients’ age. EGFR is unstable during the metastasizing, the cases of score’s transfer being exclusively characterized by the loosing of this receptor within the lymph node microenvironment. Unstable cases have a low grade of histological differentiation. The tumors with high grade of differentiation represent negative EGFR pattern. In lobular invasive carcinoma, the most of the tumors are EGFR negative, not only in the primary tumor, but also in the lymph node metastases. In this type of tumors, the values of EGFR expression depend on location, however the EGFR’ score in metastasis is directly dependent on its value in the primary tumor.